JP2007152670A - Recording medium judging method, and inkjet recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recording medium judging method which can detect the characteristics of a recorded test pattern by a comparatively simple constitution and under a high performance state. <P>SOLUTION: The test pattern in which dots are arranged by a specified pitch is recorded on a recording medium, and then, the density of an area including a plurality of the recorded dots is measured, and thus, the kind of the recording medium is judged from the obtained density. By this method, the characteristics of the recording medium can be judged by the density of the area including the plurality of dots regardless of the shapes of individual dots. That is, the kind of the recording medium can be judged under a state of a comparatively high precision without providing a reading sensor of a high resolution or a movable scanning mechanism of a high precision. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for discriminating the type of a recording medium in an ink jet recording apparatus.

  In an ink jet recording apparatus, an image is recorded on a recording medium using a recording head including a plurality of recording elements (nozzles) that eject ink based on recording data. The recording resolution is determined according to the recording density of the recording elements arranged on the recording head, and the amount of ink ejected from each recording element is also determined according to the recording resolution.

  In an ink jet recording apparatus, since an image can be formed in a non-contact manner on a recording medium, recording can be performed on various types of recording media. However, it is also known that recording conditions such as ink fixing time, maximum amount of ink that can be absorbed, and color developability vary depending on the type of recording medium. Therefore, when recording is performed on various recording media under the same conditions, for example, a recording medium having a low ink absorption rate causes a problem that ink that cannot be absorbed overflows on the surface.

  In order to avoid such a problem, it is effective to appropriately change the recording conditions by adjusting the ink application amount and the recording time according to the type of the recording medium. However, for that purpose, it is necessary to set the type of the recording medium before recording. The recording medium can be set by the user using driver software or the like. However, the recording apparatus is provided with means for detecting the type of the recording medium, and the recording condition is automatically set according to the detection result. And methods have also been proposed.

  For example, as a method for automatically discriminating the type of recording medium, a method is known in which visible light is irradiated on the surface of the recording medium and the amount of irregularly reflected light and regular reflected light are read by a light receiving sensor. According to this method, the thickness and glossiness of the recording medium are ascertained by analyzing the detected irregular reflection light quantity and regular reflection light quantity, and as a result, the type of the recording medium is determined. Hereinafter, this method is referred to as “method 1”.

  As another method for discriminating a recording medium, a method using a sensor that receives transmitted light is known. This method is effective when discriminating between an opaque recording medium such as plain paper and a transparent medium such as OHP paper. Hereinafter, this method is referred to as “method 2”.

  Furthermore, a method has been proposed in which a predetermined mark is actually recorded on a recording medium, and the type or the density of the recording medium is determined by reading the formed mark shape or density with an optical sensor (see, for example, Patent Document 1). Patent Document 1 discloses a method of recording a mark of a specific pattern on a recording medium and reading it with an optical sensor as preprocessing before recording an original image. Since the ink absorption characteristics vary depending on the type of the recording medium, the recorded mark is characterized by its shape depending on the type of the recording medium. Patent Document 1 discloses a method of discriminating the type of a recording medium by reading this shape with an optical sensor and further analyzing its characteristics.

  For example, a general size of one dot is about 100 μm in diameter. In this case, in order to accurately read the shape of one dot so that the type of the recording medium can be determined, a sensor having a resolution sufficiently higher than a pitch of 100 μm is required. However, as in Patent Document 1, when a specific pattern composed of a plurality of dots is adopted as a mark, the type of the recording medium can be determined by reading with a resolution that can grasp the difference in the shape of the mark. I can do it.

  Furthermore, Patent Document 1 records a plurality of types of marks such as a circular pattern composed of a plurality of ink droplets and a pattern for detecting a solid density, and uses information that can be acquired from each mark. Therefore, contents for improving the accuracy of discrimination are also disclosed. According to the method of Patent Document 1, as in the method 1 and method 2 described above, in a state with higher accuracy than when reading the trend of light irradiated on the surface of a recording medium on which nothing is recorded. The recording medium can be identified.

JP-A-9-193370

  However, a problem still remains in the conventional method for determining the type of the recording medium described above. For example, the method (method 1) of acquiring the irregularly reflected light amount and the regular reflected light amount of the visible light that has been irradiated has been difficult to apply to a transparent recording medium such as an OHP sheet. Since a transparent recording medium transmits visible light almost completely, the amount of irregular reflection light and regular reflection light obtained are very small, and information sufficient to define the characteristics of the recording medium cannot be obtained. As a result, compared to an opaque recording medium, there arises a problem that it takes much time to determine the recording medium or that the determination becomes impossible.

  In this case, if a reflective sensor using infrared light is added as a light source, a transparent recording medium can be detected. In addition, it is possible to simultaneously adopt the method 2 effective for discriminating a transparent medium. However, installing a plurality of light emitting / receiving means for discriminating a recording medium in the apparatus increases the cost and cannot be said to be a very suitable method.

  In recent years, applications of ink jet recording apparatuses have been diversified, and along with this, the types of recording media are increasing. For example, even if the recording medium has a white and opaque surface, there are various types such as plain paper, glossy paper, semi-glossy paper, and photo paper. That is, even if the reflectance of the surface is similar, many recording media having different ink fixing states are being provided, and these differences can be accurately discriminated only by the discriminating method such as the scheme 1 and the scheme 2. It has become difficult.

  On the other hand, the method disclosed in Patent Document 1 is a method for directly confirming ink absorption characteristics in a recording medium. Therefore, it is possible to accurately discriminate recording media having similar reflectivities and to execute optimum recording control based on the ink absorption characteristics of the recording media.

  However, the size of one dot is designed to be smaller and smaller with the recent droplet size reduction of ink jet recording. That is, in order to accurately determine the shape feature of a mark formed by a collection of smaller dots, a reading sensor with higher resolution is required even with the method disclosed in Patent Document 1. As a result, if a recent ink jet recording apparatus tries to determine a recording medium by the method described in Patent Document 1, a reading sensor having a higher resolution than before is required, and there is a concern about an increase in cost.

  Even if the sensor has sufficient resolution, if there is a discrepancy between the mark position on the recording medium and the sensor reading position, the center position and shape of the mark can be accurately grasped. I can't do it. In other words, in order to read the shape of the mark with high accuracy, the positional relationship between the sensor and the mark must be fixed to a certain degree of accuracy. In this case, if the recording element (nozzle) used for forming the mark is determined in advance and the relative position between the recording head and the sensor is fixed, the reading accuracy will not be lowered. However, since the nozzle used for recording the mark is fixed, if a discharge failure occurs in the nozzle, a desired pattern is not formed, and the recording medium may be erroneously determined.

  On the other hand, if a plurality of marks are recorded using a plurality of nozzles, the influence of variations in the ejection state of each nozzle and variations in the paper surface state can be suppressed by taking an average among the plurality of read data. Can do. However, in this case, it is necessary to move the recording medium in the nozzle arrangement direction and arrange individual marks with high accuracy at the position of the reading sensor. That is, considerable accuracy is required for attaching the recording medium conveying means and sensor, and the recording apparatus itself may be large and expensive.

  The present invention has been made to solve the above-described problems, and the object of the present invention is to detect the characteristics of a recorded test pattern with a relatively simple configuration and high performance. It is to provide a new recording medium discrimination method.

  Therefore, in the present invention, a step of recording a test pattern in which dots are arranged at a predetermined pitch on a recording medium by discharging ink from nozzles, and a predetermined area including a plurality of dots arranged at the predetermined pitch. A step of measuring a density; a step of determining a density D corresponding to the recording medium based on the density; and a step of determining a type of the recording medium based on the density D. .

  An image forming apparatus that forms an image on a recording medium using a recording head that ejects ink from nozzles, the unit configured to record a test pattern in which dots are arranged at a predetermined pitch on the recording medium, and the predetermined pitch A density sensor for measuring a density of a predetermined area including a plurality of dots arranged in the step, means for determining a density D corresponding to the recording medium based on the density, and a plurality of densities corresponding to a plurality of types of recording media Means for storing a density table storing values, means for discriminating the type of the recording medium by comparing the density D with the plurality of density values, and the type of the recording medium obtained by the discriminating means And means for storing.

  According to the present invention, even in an ink jet recording apparatus that records small dots with a high recording resolution, a recording medium with a relatively high accuracy can be obtained without a high-precision reading sensor or a high-precision moving scanning mechanism. Can be discriminated.

  FIG. 1 is a block diagram for explaining a control configuration of a recording apparatus 20 applicable to the present invention. In the figure, reference numeral 1 denotes a density sensor for discriminating the type of recording medium, which is a reflection type composed of a visible light LED and a photodiode. Reference numeral 2 denotes a recording head that discharges ink from individual recording elements in accordance with a recording signal. Recording elements (nozzles) that discharge ink of the same color are arranged at a pitch of 1200 dpi (dot / inch; reference value). . The recording head 2 of this embodiment is a multi-head that discharges four colors of cyan, magenta, yellow, and black. Reference numeral 13 denotes an end position sensor for detecting left and right ends of the recording medium.

  The density sensor 1, the recording head 2, and the end position sensor 13 are mounted on the carriage unit 5 that moves and scans in the direction of the arrow X together with the relay substrate 4 that exchanges data with them. Here, the recording head 2 and the density sensor 1 are positioned so as to scan the same area of the recording medium in the same scanning in the X direction. An ink tank for supplying ink to the recording heads for each color is also mounted on the carriage unit 5 and configured to supply ink from the upper part of each recording head.

  The relay board 4 moves in the X direction together with the carriage unit 5, but data exchanged by the relay board 4 is transmitted / received to / from the main board 6 fixed to the recording apparatus main body via the flexible cable 15.

  The main board 6 is equipped with a CPU 7 that controls the entire recording apparatus 20. The CPU 7 temporarily stores A / D converters (ADC) 8 for A / D conversion of various received data and recording data. A memory 9 or the like for storing data is provided. The main board 6 is connected to a host device 19 connected to the outside of the recording device 20, receives image data created by the host device 19, and notifies the host device 19 of the status of the recording device 20. You can do it.

  Driver software for controlling the recording device 20 is installed in the host device 19 of this embodiment. The recording medium discrimination sequence and recording mode specific to the present invention are set by the user via the driver software, and the contents set by the user are transmitted from the host device 19 to the recording device 20.

  Reference numeral 10 denotes a carriage unit conveying device, which receives a signal from the CPU 7 and moves the carriage unit 5 in the X direction at a predetermined speed. The carriage unit conveying device 10 is provided with a set of parts necessary for conveyance such as a roller, a gear, a motor, a rail, and a belt for moving the carriage unit 5.

  Reference numeral 11 denotes a recording medium transport device, which receives a signal from the CPU 7 and transports the recording medium in a direction crossing the X direction. The recording medium transport device 11 includes a set of necessary components such as a roller, a gear, a motor, and a belt for feeding the recording medium. A platen 12 supports the recording medium being recorded from below. In the recording medium 3 conveyed on the platen, there may be a concern about the floating, but in the present embodiment, such a floating is sufficiently suppressed by the roller provided in the recording medium conveying device 11. Yes. Therefore, the obtained density data is not affected by the variation in the distance between the density sensor 1 and the recording medium.

  Reference numeral 16 denotes a home position sensor (HP sensor) for detecting the initial position (HP) of the carriage unit 5. When the HP sensor 16 detects the carriage unit 5, the initial position of the carriage unit 5 is determined. Thereafter, even if the carriage unit 5 moves, the moving distance from the HP is accurately grasped by an encoder sensor and an encoder scale (not shown).

  Reference numeral 18 denotes an operation panel (OP) for notifying the user of the status of the recording apparatus.

  2A and 2B are a top view and a side view for explaining the mechanism of the recording apparatus 20 of the present embodiment. A paper feed cassette 17 containing a plurality of recording media 3 is detachably mounted at a position below the recording unit of the main body of the recording apparatus 20. The mounting of the paper feed cassette 17 is detected by a sensor (not shown).

  When the recording operation starts, one recording medium on the uppermost surface of the paper feeding cassette is fed into the recording apparatus 20 and can be recorded by the recording head 2 on the recording position in the apparatus, that is, on the platen 12 by the U-turn path. It is transported to the position. At this time, the leading end of the recording medium is detected by a leading end detection sensor 14 installed in the apparatus. Thereafter, a recording main scan in which the carriage unit 5 moves in the X direction while discharging ink from the recording head 2 and a sub-scan in which the recording medium is conveyed in the Y direction by a predetermined amount according to the recording width in the recording main scan. By repeating alternately, an image is gradually formed on the recording medium 3.

  In the following description, it is assumed that the same type of recording medium is set in the paper feed cassette 17. In other words, unless the attachment / detachment of the paper feed cassette 17 is particularly confirmed, it can be determined that the next recording is performed on the same type of recording medium as the previous one. Therefore, in the recording apparatus of the present embodiment, the recording medium determination mode can be executed at the timing when the attachment / detachment of the paper feed cassette 17 is detected.

  FIG. 3 is a flowchart for explaining a series of steps performed by the CPU when it is detected that the sheet feeding cassette is mounted in the recording apparatus in the standby state.

  In step 301, the recording apparatus in the standby state proceeds to step S302 at predetermined time intervals, and determines whether or not the paper feed cassette has been set. If it is determined that the process has not been performed, the process returns to step S301 to continue the standby state. On the other hand, if it is confirmed that the paper cassette is set, the process proceeds to step S303.

  In step S303, a display for prompting the user to select whether or not to determine the type of the recording medium is performed on the OP panel. At the same time, the status information of the recording device is transmitted to the host device 19. The driver software installed in the host device 20 receives this information and displays a similar pop-up message on the monitor screen. The user confirms this, and selects execution / non-execution of the recording medium determination mode from the driver software.

  In step S304, the input by the user is determined. If it is determined that non-execution has been selected by the user, the process advances to step S306 to enter a recording command wait state. On the other hand, if execution of the recording medium determination mode is selected by the user, the process advances to step S305 to execute the recording medium determination mode. Details of the recording medium determination mode will be described later with reference to FIG.

  In step S305, when the recording medium determination mode is executed and the type of the recording medium accommodated in the currently loaded cassette is determined, the process proceeds to step S306, and the presence or absence of a recording command is confirmed. If the recording command is not confirmed, the routine is repeated until the recording command is confirmed, and the recording command wait state is entered.

  When the recording command is confirmed in step S306, the process proceeds to step S307 and an image is recorded in accordance with the set recording mode. Details of the recording sequence will be described later with reference to FIG.

  When the recording sequence ends, the process returns to step S306 again to continue the recording command waiting state. If it is confirmed in the recording command waiting state that the paper cassette is set, the process jumps to step S302.

  FIG. 4 is a flowchart for explaining each process executed by the CPU 7 in the recording medium discrimination mode of the present embodiment.

  When the recording medium determination mode is started, first, the process proceeds to step S401, and test pattern recording is executed. Specifically, the uppermost recording medium in the paper feeding cassette is fed into the apparatus main body and conveyed to the recording position after the U-turn pass. When the recording paper leading edge detection sensor 14 detects the leading edge of the recording medium 3, accurate alignment with respect to the Y direction is performed.

  Next, the output of the recording paper edge detection sensor 13 is sequentially acquired while moving the carriage unit 5 in the direction opposite to the HP using the carriage unit transport device 10. While the carriage unit 5 is moved within the entire movable range, the recording paper edge detection sensor 13 detects the right edge and the left edge of the recording medium. The recordable width of the recording medium is acquired at this detection timing.

  Next, a predetermined test pattern is recorded on the recording medium 3 while controlling the conveyance of the carriage unit 5 and the ink discharge of the recording head 2 so as to be within the obtained recordable width.

  FIGS. 5A and 5B are schematic diagrams for explaining the relationship between the test pattern in the present embodiment and the aperture of the density sensor 1 that reads the test pattern. FIG. 5A is a diagram for explaining the aperture size of the density sensor 1. In this embodiment, the size corresponds to 30 dpi, that is, an area of about 847 μm square.

  FIG. 5B shows the test pattern of this embodiment, in which a plurality of dots are recorded at equal intervals in the vertical and horizontal directions. The ink color applied to record each dot may be selected to have a color that most closely matches the spectral sensitivity characteristics of the light source provided in the density sensor 1. This is because it is desired that the density sensor 1 that reads the pattern acquires the SN ratio between the positions where the dots are recorded and the positions where the dots are not recorded in a relatively high state. The density sensor 1 of the present embodiment includes a green LED as a light emitting element and a photodiode having sensitivity characteristics in the visible range as a light receiving element. Then, black ink is selected as the color corresponding to the green LED with the highest sensitivity, thereby recording the test pattern shown in FIG.

  In the present embodiment, individual dots are recorded at intervals corresponding to 120 dpi, that is, at intervals of about 212 μm. Since the recording head of this embodiment has a nozzle resolution of 1200 dpi, the above resolution can be realized by discharging every 10 nozzles. The interval is not particularly limited in the present invention, but it is preferable that the distance is close enough that adjacent dots do not overlap each other even in the recording medium in which ink is most likely to spread. As will be described in detail later, in the present invention, the type of the recording medium is determined by using the fact that the difference in the area of each dot affects the density of the test pattern within the aperture size. Therefore, a recording state in which the difference in area of individual dots clearly appears is required. On the other hand, dots must be recorded at a density that does not exceed the ink absorbable amount on a recording medium that has the smallest ink absorbable amount.

  The density sensor 1 of this embodiment does not include an optical system such as a lens in the light receiving element, and has a simple configuration in which a window is formed in front of the light receiving surface. Therefore, the reading resolution of the sensor is not so high, and the aperture size is about 30 dpi, that is, about 847 μm square.

  The aperture size of the density sensor 1 is about 847 μm square, but the test pattern records dots in a wider range. In this way, even if a slight error is included between the pattern recording position and the reading position of the density sensor 1, a stable number (16 in this case) is included in the aperture of the density sensor 1. Dots can be present. In the present embodiment, a test pattern as shown in FIG. 5B is recorded over a wide range or several places so that the concentration measurement can be performed a plurality of times at different positions.

  FIG. 6 is a schematic diagram showing a recording example of the test pattern described in FIG. In this example, a test pattern is recorded over the entire recordable width of the recording medium in the sub-scanning direction and in the main scanning direction. As already described with reference to FIG. 1, the recording head 2 and the density sensor 1 of this embodiment are arranged to scan the same area of the recording medium in the same main scanning. In the case of the test pattern as in this example, it is not necessary to carry the recording medium between the main scan for test pattern recording and the main scan for density reading. Therefore, a plurality of density measurements can be performed at a plurality of different positions on the test pattern in one main scan for reading.

  Returning again to the flowchart of FIG. When the test pattern is recorded in step S401, the CPU 7 returns the carriage unit 5 to HP and waits for a predetermined time until the recorded ink is sufficiently fixed on the recording medium. Thereafter, the process proceeds to step S402.

  In step S402, the carriage unit 5 is moved to a position where the test pattern recorded by the density sensor 1 can be read, and the density of the test pattern is detected by the density sensor 1. With the test pattern shown in FIG. 6, the density measurement can be performed a plurality of times during one main scan. The output signal of the density sensor 1 is transmitted from the relay board 4 via the flexible cable 15 to the CPU 7 of the main board 6 and is AD converted by the ADC 8. An average value of a plurality of density values is calculated from the obtained digital data, and this value is set as a density value D of the recording medium. When density measurement is performed a plurality of times in the same main scan as in the pattern of FIG. 6, the number of density measurements, that is, the number of digital data obtained is determined by the moving speed of the carriage unit and the conversion speed capability of the ADC.

  FIGS. 7A to 7C show different states of dots formed on a recording medium when dots are recorded as shown in FIG. 5B. It is a diagram shown for each of glossy paper and plain paper. FIG. 7A shows dots formed on a recording medium having a relatively low ink absorption such as OHP paper. In a recording medium with low ink absorbability, the applied ink does not immediately penetrate into the recording medium, so that the ink is gradually fixed in a condensed state due to surface tension. Therefore, the shape of the formed dots is round and small.

  FIG. 7B shows dots formed on a special paper provided with an ink receiving layer having a high ink absorbability such as semi-glossy paper. In a recording medium having high ink absorbability, the applied ink penetrates not only in the depth direction of the recording medium but also in the periphery thereof, so that the shape of the formed dot is round, but the diameter is OHP. Greater than paper.

  FIG. 7C is a diagram showing dots formed on plain paper. In the case of plain paper, the ink absorbency is high and the ink spreads widely along the fibers of the paper that are entangled irregularly. As a result, the shape of the formed dots is non-uniform and the area is the largest among the three types of recording media.

  In this embodiment, the aperture size of the density sensor 1 is about 847 μm square, and about 16 dots are recorded in this area. In the case of the test pattern of the present embodiment in which a plurality of dots do not overlap each other, the output density is determined by how much area of the blank area within the aperture size is covered with ink (coverage ratio). That is, the value of the density D obtained is the lowest among the three papers on the OHP paper with the smallest individual dot area, and the highest among the three papers with the plain paper with the largest individual dot area.

  Again, it returns to the flowchart of FIG. When the density value D is obtained in step S402, the recording medium on which the test pattern is recorded is discharged, and the process proceeds to step S403. In step S403, the density value table stored in the apparatus is referred to, and various data stored here are compared with the obtained density value D.

  FIG. 8 is a diagram for explaining a density value table stored in the recording apparatus main body. Here, five standard density values a to e corresponding to five typical recording media are stored. The CPU selects a density value closest to the density value D from a to e, and determines a recording medium type corresponding to the density value as a discrimination result (step S404).

  Thereafter, the process proceeds to step S405, and the obtained recording medium information is stored in a predetermined memory area in the recording apparatus. Thus, the recording medium discrimination mode is completed, and the process returns to the flowchart shown in FIG.

  FIG. 9 is a flowchart for explaining each step executed by the CPU 7 in the recording sequence in step S307 described in the flowchart of FIG.

  When the recording sequence is started, the CPU receives the recording data from the host device 19 and sequentially stores it in the memory in the device (step S901). The head portion (header) of the recording data includes information on the recording medium set by the user on the driver software.

  In step S902, the CPU checks the consistency between the type of recording medium set by the user on the driver software and the type of recording medium obtained in the recording medium determination mode. If it is determined in step S903 that there is consistency, that is, it is determined that the type of the recording medium set by the user on the driver software matches the type of the recording medium obtained by the recording medium discrimination mode, the process proceeds to step S904. On the other hand, if it is determined in step S903 that there is no consistency, that is, it is determined that the type of the recording medium set by the user on the driver software does not match the type of the recording medium obtained by the recording medium discrimination mode, the process proceeds to step S905. .

  In step S905, a message indicating that the recording medium type selected by the driver software and the information on the recording medium type acquired in the recording medium discrimination mode do not match is displayed on the OP.

  In step S906, the CPU 7 accesses the host device 19 to cause the driver software to display a pop-up message having the same content as OP on the monitor. Further, the driver software displays a message prompting the user to select whether to start recording with the set recording medium type or to change the recording medium type.

  In step S907, it is determined whether to start recording with the setting of the recording medium type input from the driver software or to change the recording medium type from information input to the driver software again by the user. If it is determined in step S907 that the recording medium type is to be changed, the process proceeds to step S908, and information on the new recording medium type by the user is received from the driver software. Thereafter, the process returns to step S902, and the consistency between the type of the recording medium newly set on the driver software and the type of the recording medium obtained by the recording medium discrimination mode is checked again.

  If it is determined in step S903 that the two recording medium types are consistent, or if the user determines to start recording with the recording medium type setting input from the driver software in step S907, the process proceeds to step S904. . Then, recording is performed according to the recording mode corresponding to the type of the recording medium that has already been determined. Thereafter, the process returns to the flowchart described in FIG.

  According to the configuration described above, even when the individual dot diameter recorded in the test pattern is small, a plurality of dots are detected macroscopically by the density sensor having an aperture size much larger than the individual dot diameter. Thus, the type of the recording medium can be determined. In this case, it is sufficient that the optical density in the predetermined aperture can be detected, so that the object can be achieved even if a density sensor having a relatively simple configuration is used. In addition, by recording a uniform test pattern in a wider range than the aperture, even if there is a slight deviation between the test pattern recording position and the sensor reading position, the obtained result will not be affected. Absent. Furthermore, since a plurality of dots recorded by a plurality of different nozzles are detected by a single reading operation, the influence of ejection variations of individual nozzles is suppressed in advance.

  That is, according to the present invention, even an ink jet recording apparatus that records small dots with high recording resolution does not include a high-precision reading sensor or a high-precision moving scanning mechanism as described in Patent Document 1. The type of the recording medium can be determined with high accuracy.

In the embodiment described above, the density sensor having the green LED light emitting element is dealt with by recording the test pattern with black ink, but of course, the present invention is not limited to such a combination. . As described above, the ink for recording the test pattern may be any ink that matches the spectral sensitivity characteristics of the light source provided in the density sensor as much as possible.
Therefore, for example, if the light emitting element is a blue LED, it can be said that it is appropriate to use yellow ink for the test pattern. Since the test pattern recorded with only yellow ink is expected to be visually inconspicuous, the test pattern may be recorded in the margin of the actual image. In this case, since the recording medium is not consumed for the recording medium discrimination mode, an effect of reducing the running cost can be obtained.

  In the above embodiment, the result of the recording medium discrimination mode is used for checking and optimizing the recording medium type set by the driver software. However, the present invention is not limited to this. For example, the present invention is effective even in a configuration in which the result of the recording medium discrimination mode is prioritized and the recording method is appropriately changed or the parameters used for image processing are changed. Furthermore, the setting of the recording medium type from the driver software is not an essential requirement for the present invention, and the recording mode may be set only in accordance with the result of the recording medium determination mode.

  In the above description, the recording mode is changed according to the type of the recording medium. Generally, however, in addition to the type of the recording medium, there are various types according to various setting conditions such as the type of image, the quality, and the recording speed. A recording mode is available. However, the intention of the present invention does not change in the sense that a recording mode suitable for each recording medium is set based on the type of the recording medium.

  In the above-described embodiment, the step of automatically urging the recording medium determination sequence after the paper feed cassette is set is performed. However, the timing for performing the recording medium determination sequence is not limited to this. The effect of the present invention does not change whether it is performed as needed by the user or performed every time a recording command is received. Further, the present invention is effective even when the recording medium is not supplied from the paper feed cassette, but is configured to record on roll paper, for example.

  Furthermore, in the above embodiment, the recording system in which the host device is connected to the outside of the recording device has been described, but the present invention is not limited to such a configuration. Even if there is no external host device or driver software, a CPU, an operation panel (OP), and an operation button on the OP provided in the recording device are prepared, and the same as in the above embodiment. An effect can also be obtained. Conversely, even if the recording device does not have an operation panel, it is possible to handle all of them with driver software.

FIG. 3 is a block diagram for explaining a control configuration of a recording apparatus applicable to the present invention. (A) And (b) is the top view and side view for demonstrating the mechanism of the recording device of this embodiment. 6 is a flowchart for explaining a series of steps performed by a CPU when attachment of a paper feed cassette is detected in a recording apparatus in standby. It is a flowchart for demonstrating each process which CPU performs in the recording medium discrimination | determination mode of embodiment of this invention. (A) And (b) is a schematic diagram for demonstrating the relationship between a test pattern and the aperture of a density sensor. It is the schematic diagram which showed the example of recording of the test pattern. (A)-(c) is the figure which showed the mode of the dot formed on a recording medium for every different kind of recording medium. FIG. 6 is a diagram for explaining a density value table stored in a recording apparatus main body. It is a flowchart for demonstrating each process which CPU performs in a recording sequence.

Explanation of symbols

1 Density Sensor 2 Recording Head 3 Recording Medium 4 Relay Board 5 Carriage Unit 6 Main Board 7 CPU
8 ADC
DESCRIPTION OF SYMBOLS 9 Memory 10 Carriage unit conveying apparatus 11 Recording medium conveying apparatus 12 Platen 13 End position sensor 14 End detection sensor 15 Flexible cable 16 Home position sensor 17 Paper feed cassette 18 Operation panel 19 Host apparatus 20 Recording apparatus

Claims (11)

Recording a test pattern in which dots are arranged at a predetermined pitch on a recording medium by discharging ink from nozzles;
Measuring a density of a predetermined area including a plurality of dots arranged at the predetermined pitch; and
Determining a density D corresponding to the recording medium based on the density;
And a step of discriminating the type of the recording medium based on the density D. Prepare a density table in which multiple density values corresponding to multiple types of recording media are stored,
The recording medium determination method according to claim 1, wherein in the determination step, the type of the recording medium is determined by comparing the density D and the plurality of density values.   3. The recording medium discrimination method according to claim 1, wherein the predetermined pitch is an interval at which adjacent dots do not overlap each other.   The recording medium determination method according to claim 1, wherein the predetermined pitch is an interval that does not exceed an ink absorbable amount of the recording medium.   5. The recording medium according to claim 1, wherein in the density measurement step, the density of the predetermined area is measured using a sensor having a resolution lower than the resolution corresponding to the predetermined pitch. How to determine.   The recording medium determination method according to claim 1, wherein a recording area of the test pattern is larger than the predetermined area.   The density of the predetermined area at a plurality of locations is measured in the measurement step, and the density D is determined from an average value of the density of the predetermined area at the plurality of locations in the determination step. 7. The recording medium discrimination method according to any one of 6.   8. The recording medium discrimination method according to claim 1, wherein the density measuring step is performed after a predetermined waiting time after the recording step. An inkjet recording apparatus that forms an image on a recording medium using a recording head that discharges ink from a nozzle,
Means for recording a test pattern in which dots are arranged at a predetermined pitch on a recording medium;
A density sensor for measuring the density of a predetermined area including a plurality of dots arranged at the predetermined pitch;
Means for determining a density D corresponding to the recording medium based on the density;
Means for storing a density table storing a plurality of density values corresponding to a plurality of types of recording media;
Means for determining the type of the recording medium by comparing the density D and the plurality of density values;
An ink jet recording apparatus comprising: means for storing the type of the recording medium obtained by the determining means.   The inkjet recording apparatus according to claim 9, further comprising means for setting a recording mode for recording an actual image according to the type of the recording medium stored in the storage unit. Means for moving and scanning the recording head and the density sensor relative to the recording medium;
11. The ink jet recording apparatus according to claim 9, wherein the density of the predetermined area at a plurality of locations of the test pattern is measured by the sensor during one moving scan.

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